The present invention relates to an electronic control device.
FIG. 15 shows a conventional electronic control device 100 including electronic components 102 and a connector 103 mounted on a plane of a circuit substrate (i.e. printed substrate) 101 which are accommodated in a metal-made casing 107 (for example, refer to Japanese Patent Application Laid-open Nos. 2001-168545 and 2002-134939).
In the electronic control device 100 shown in FIG. 15, the connector 103 consists of a connector housing 103a and a plurality of connector pins 103b. The circuit substrate 101 has through-holes 104 into which the connector pins 103b of the connector 103 are inserted and bonded by solder. The circuit substrate 101 is fixed to the casing 107 by means of screws. The casing 107 is closed with a cover 108 and the connector 103. According to this conventional electronic control device 100, water-proof arrangements are employed for the coupling portion of the connector 103 and the casing 107 (or the cover 108) as well as for the coupling portion of the casing 107 and the cover 108. More specifically, silicone adhesive 109 is applied to these coupling portions to seal the inside space of the electronic control device 100.
According to this kind of electronic control device, due to recent advancement of high-density mounting techniques, the surface available for electronic components other than the connectors remains in a narrowly limited region on the circuit substrate. However, regarding the connector, its size tends to be increasing because the number of required pins is increasing due to functions required for recent electronic control devices.
In this respect, according to the conventional mounting structure disposing a large connector and various electronic components on the same plane of one substrate, it is difficult to downsize the circuit substrate and accordingly the entire size of the electronic control device cannot be reduced.
Especially, according to an electronic control device installed in an automotive vehicle, the number of required pins of the connector reaches approximately 200 to realize advanced functions of automotive vehicles for example to control engines and/or automatic transmissions. Furthermore, there is the tendency that recent automotive vehicles secure larger occupant spaces. On the other hand, the space available for the electronic control devices is decreasing. Accordingly, it is necessary to effectively reduce the size of the electronic control device so that the electronic control device equipped with a large connector can be installed in a limited space of an automotive vehicle.